In recent years, there has been an increasing demand for high integration of chips in a package via size reduction and the thinning of mounted semiconductor silicon chips (hereinafter, referred to as chips) as the functionalities of a mobile phone, a digital AV device, an IC card, or the like are added. In an integrated circuit, for example, representatively a chip size package (CSP) or a multi-chip package (MCP), in which a plurality of chips are built into one package, the chip is required to be further thinned. It is necessary to reduce the thickness of a chip to a range of 25 μm to 150 μm so as to realize high integration of chips in a package.
Meanwhile, since a semiconductor wafer (hereinafter, referred to as a wafer), that is, a basis for a chip is thinned via grinding, the strength of the wafer becomes low, and a crack or warping is likely to occur. Since it is difficult to automatically transport wafers having low strength associated with the reduction of the thickness, the wafers are required to be manually transported, and the handling thereof is complicated.
Such a challenge has lead to the development of a wafer handling system in which it is possible to maintain the strength of a wafer, and to prevent occurrences of a crack and warping on the wafer by attaching a plate, a so-called support plate made of glass, silicon, hardened plastic, or the like to the wafer to be grinded. Since it is possible to maintain the strength of the wafer via the wafer handling system, it is possible to automate the transportation of thinned wafers.
In the wafer handling system, the support plate is attached to the wafer via an adhesive layer formed from an adhesive tape, thermoplastic resin, an adhesive, or the like.
PTL 1 discloses an attachment method and an attachment apparatus to perform the attachment operation, which includes a setting plate on which a substrate is set, a presser plate configured to press a support plate against the substrate, a pair of horizontally advanceable and retractable alignment members, in which a tip end portion of the alignment member is provided with a blade configured to support a lower surface of a circumferential edge portion of the support plate, and a presser member configured to position the substrate and the support plate in a state where the support plate overlaps the substrate. PTL 2 discloses an overlapping unit and an attachment apparatus which include a support unit configured to support a wafer or a support plate, and a transportation unit configured to transport the wafer or the support plate, and in which the support unit includes three or more columnar members having a first support portion configured to support an end portion of the wafer or the support plate, and a first positioning portion configured to guide the end portion to the first support portion.